Mines and industrial sites are becoming increasingly more networked. Emerging safety requirements in the US and internationally, demand real-time wireless communications for voice and data. Process control and other operations are increasingly monitored by hand-held data devices and/or centralized IP
These new networking applications create expectations of high performance over many
wireless "hops" (node to node relays), with dependable support for video, voice, and data.
Miners Give A Nod
Remote Real Time Video
Monitoring of Longwall Shearers.
With this increased focus on safety in underground coal mines, efforts are being made to reduce risks to miners in any way possible.
In "Longwall" mining the mine roof is expected to fall when operations are concluded. For this reason, roof supports are not as extensive at the working mine face. This holds obvious danger to the miners operating at the mine face using the mining machines called "shearers".
One way to reduce this risk is to remove the miners from the immediate area as much as one mile. But to efficiently operate the shearer, the miner must still be able to see the coal face, a problem from a mile away.
One option was putting full motion high resolution video cameras
on both working ends of the shearer (the shearer operates both forward and backward).
Because of the nature of the mining process, there cannot be any meaningful delay in the image from the video camera to the machine operator. This demands minimal delay and jitter for the video connection.
MD4000 Mesh nodes are supporting the operation of monitoring precision heavy
mining machinery remotely, providing connectivity for high quality video over the multiple hops necessary to ensure that miners are removed to a safe operating zone.
Operators are able to observe the operation and performance of the machine, adjusting controls as necessary without exposing themselves to the dangers of the immediate area being mined.
The MD4000 network provides a consistent throughputwith a 5.8 GHz backhaul, more than enough to support the two 15fps video cameras with PTZ controls. Delays through each MD4000 node are only 1-2 milliseconds, providing the real-time video necessary for successful remote operation.
Rapid Set up and Tear down of
Meshdynamics Mesh Nodes
Because of the dynamic nature of the typical Longwall mining operation, the mine itself is constantly being reconfigured. As the mine face moves forward, sections of the mine are allowed to collapse and new areas are opened. As part of this deployment, it was demonstrated the MD4000 network instantaneously and automatically adapts to the changing environments. MD4000 nodes may be redeployed to new areas of the mine as these are opened, joining the existing network to provide coverage for the video application. No complex network engineering is required.
With this network in place to provide remote operation of the
Longwall shearer, it is also possible to extend the network to the surface and connect it to the PBX/phone system and other data and voice network. This could ease the maintenance and support of the mining machinery by allowing real-time phone support at the site of the operators and/or equipment as well as to allow access to on-line technical documentation from underground.
Successful "Room and Pillar" demonstrating
effective VOIP communications and asset tracking.
In multiple successful demonstrations, working "room and pillar" mines
required long distance connectivity for voice, location
tracking, and video process monitoring. Because the
headquarters and processing plant is some distance from the
main entry to the mine, multiple hops were needed both
outside and inside the mine, a total distance of 3˝ miles.
nodes are installed in a number of locations within the mine itself, secured to the roof or supporting timbers as appropriate for each location and powered by a battery back-up system.
Voice connectivity is provided from wireless Wi-Fi Voice-over-IP (VoIP) handsets carried by individual miners to the PBX at the headquarters site, with PSTN
(Public Switched Telephone Network) access via the PBX.
We have demonstrated clear real time VOIP multicast (push to
talk) communications over a 50+ hop string of pearls
wireless mesh chain in a coal
mine. 150 mesh nodes were employed in the test,
with multiple pathways each with nodes in a string of pearls
chain. VOIP multicast traffic was successfully tested
over 50 hops, end to end.
A miner location and tracking system based on Wi-Fi
is also supported over the
Meshdynamics wireless infrastructure. Along with the two-way voice communications, this helps to fulfill the MINER Act requirements. In addition, an IP-based video camera is being used to monitor remotely a key junction of the belt system that is crucial to mine productivity.
Meshdynamics Technology Benefits for Mining
The key to these successful demonstrations is the ability to provide very high performance for high-quality
video and voice over a large number of hops. While most Wi-Fi mesh solutions would fail after a handful of hops,
Meshdynamics' patented and patent-pending solutions begin by providing two backhaul radios to each node. To overcome the problems of congestion and contention one radio is used to create a link to its upstream (nearer the wired source or "root") node. Another radio creates a link downstream to the next neighbor node.
Thus, each node may be sending and receiving simultaneously to its upstream and downstream neighbors, unlike most competitive solutions, which must continually "turn around" between sending and receiving upstream and downstream. Because each link is managed independently, the available channels may be re-used across the network. This expands the available spectrum, increasing performance of the network 50 times or more compared to traditional mesh solutions, delivering the video performance necessary for efficient real-time remote observation and control of the mining machinery.
Meshdynamics' third generation patented
mesh networking software creates an RF-aware "radio robot" in each MD4000 node. This distributed dynamic radio intelligence constantly monitors the surrounding radio environment. The node locates adjacent nodes in the network as they are added. Based on this continual scanning of the environment, the
Meshdynamics nodes form a network in an independent, but coordinated fashion, with relationships based on highest performance, interference rejection, and optimal re-use of channel assignments for maximal network bandwidth. In the remote mining environment, this continuously and automatically adapts the MD4000 network to the changing configuration of the mine and locations of the mining machinery.
Meshdynamics provides this networking power in a compact, robust enclosure
equiring little room in the cramped underground environment. Low power draw and available battery power solutions permit use in harsh environments and provide back-up functionality in case of power failure or other incidents.
Our dynamic radio intelligence allows nodes to be installed and supported easily, without costly site surveys and pre-engineering.
Meshdynamics products also include
intrinsically safe technologies
for deployment in severe environments, as well as specialized support for
and other real-time
Mining Industry Related Links:
Miners give a nod
(Courtesy Mission Critical Magazine, July 2008)
Meshdynamics First With Persistent Voice Over Wireless Mesh
Meshdynamics Delivers Persistent Wi-Fi Network for Mobile
Meshdynamics Partner in Underground Mining Communications
strengthens position with MSHA approval
Warning And Reporting Network (JWARN)
Analysis of over 100+ mesh vendors by Battelle Institute
Overview of configuration options including
3.3VDC explosion proof enclosures.
Frequently asked Questions
Antenna selection, GPS, Mobility extensions, Hazard proof